Tube upgrade/rolling question

Last time I checked, Mapleshade does not build a brass damper for a 300B tube. Perhaps Brauser was suggesting them for the smaller tubes. The largest available, unless they've come out with something new, is an Anchor C which is for an EL34-sized tube. You can, however, buy a nylon damper for a 300B tube from Herbies (Hal-O dampers). I doubt very much whether any of them will make anywhere near as much of a sonic difference as going to a better tube, which would not be difficult given what you have in there. That is not to say the dampers are not a worthy investment, but that improving the tube will give way more bang for the buck IMO. I love the Western Electric I use in my amps, but you need to sign away your first born child to get a pair. Short of that I'd look at the newest issue of the Svetlana 300B tube (they were having problems with the 300B for a while, but the brand new ones are supposed to be pretty good). TJ's, JJ Tesla, and Valve Art would all offer improvements over Chinese IMHO. I had a pair of Chinese tubes for my amps and they sounded truly awful in comparison to the WE's. I read a recent review (a 300B shootout) ...cannot recall where, that claimed the newer Svet came very close to the WE in terms of putting it all together in a 300B tube. Perhaps someone else could recall where that review was.

Marco

Brauser, I was warned that the surround type of brass dampers from Mapleshade may be more able to hold in the tube heat, shortening tube life, rather than making it easier for heat to escape into the air, as the manufacturer believes.
What is your knowledge regarding this claim, made by someone who was using a different company's damper?

Western Electric made the best 300B's. 300B tubes are still being produced on the old Kansas City production line by Westrex and licensed under the Western Electric name. The new WE production tubes are expensive, maybe more so than NOS tubes. I would prefer the NOS tubes.

Thanks guys fr your inputs. I've ordered a matched pair of JJ 300B's. I should get them them tomorrow and I'll let you know of the results.
I found out that the 6K7 can be interchanged with 6S7, KTW63, NR81, and CV1941 - are any of them more prefferable than others?

Here is the review from Stereophile I was thinking of. It was a follow up from an article titled "In Search of the Perfect 300B". The conclusion of that article, as in pretty much ever one I've ever read, was that the Western Electric is the cream of the crop. However, if you read the follow-up link above, you'll see where the reviewer in this case thought the brand new Svetlana's came very close to the WE's, more so than any other 300B they tested. For whatever that may be worth / YMMV / I have no direct experience with the new Svets.

Zoya - I'm sure the JJ's will improve over the stock Chinese tubes. Don't forget they do take a while to burn-in. Give them a few hundred hours of play time before making a judgment. From the same review I mention, here is what the reviewer had to say about the JJ:

JJ Electronics 300B: $199/pair. As tall as the KR, but not quite as heavy. Gold wire is used for the grid, and the grid supports are supplied with cooling fins (unusual in a 300B). Worked well in both amps. Very good bass—real pressure there—but with a trace of "hollow" coloration in the midbass when used in the AudioNote. Very involving, even euphonic—almost as if trying to make things nicer than real. Quite open, but a very thin veil was noticeable that resulted in a subtle soft-focus effect. Good dynamics, reasonably fine detail, threw a remarkably wide stage with the AudioNote. Lost some control in complex music. Rhythm okay, but rather speedy and not totally relaxed.

Marco